Skeletal System: Functions, Classification, Structure, and Formation

Comprehensive vocabulary flashcards covering the skeletal system, bone classifications, bone anatomy and microstructure, fracture repair, and bone formation.

Bone/Osseous Tissue

Hard, dense connective tissue that forms the support structure of the body.

Cartilage

A semi-rigid form of connective tissue that provides flexibility and smooth surfaces for movement.

Skeletal System

A body system made of bones and cartilage that supports the body, facilitates movement, protects organs, produces blood cells, and stores and releases minerals and fats.

Yellow Marrow

Bone marrow containing adipose tissue that functions in fat storage.

Red Marrow

The region within bone where the production of red blood cells takes place.

Hematopoiesis

The production of red blood cells.

Bone Matrix

A reservoir for important minerals within the skeletal system.

Long Bones

Bones that are cylindrical in shape, longer than wide, and function as levers (such as the femur, tibula, and fibula).

Short Bones

Cube-like bones that are equal in length, width, and thickness, functioning in support and stability (such as carpals and tarsals).

Flat Bone

A thin, flat, and curved bone that functions in muscle attachment and internal organ protection (such as skull bones, scapulae, sternum, and ribs).

Irregular Bones

Bones with no easily characterized shape, exemplified by the vertebrae and several facial bones.

Sesamoid Bones

Small and round bones that function to protect tendons, such as the patella and tendons between the thumb and forefinger.

Coteogenic cells

Undifferentiated cells with high mitotic activity that are the only bone cells that divide, developing into osteoblasts.

Osteoclasts

Multinucleated cells on bone surfaces that originate from white blood cells and are responsible for bone reabsorption or breakdown.

Osten

The microscopic structural unit of compact bone composed of lamella.

Lamella

A concentric ring of calcified matrix that makes up an osteon.

Central canal

A channel running down the center of each osteon that contains blood vessels and nerves.

Perforating canal

Canals where blood vessels and nerves branch off at right angles.

Nutrient foramen

Small openings in the diaphysis where blood enters the bone.

Closed reduction

Setting a broken bone by manipulating it back into its natural position without surgery.

Open reduction

A procedure that requires surgery to expose the fracture and reset the broken bone.

Growth hormone

A hormone that controls bone growth.

Thyroxine

A hormone that promotes osteoblastic activity and the synthesis of bone matrix.

Diaphysis

The tubular shaft running between the proximal and distal bone edges.

Medullary Cavity

The hollow region within the diaphysis that is filled with yellow marrow.

Compact Bone

Dense and hard bone tissue that makes up the walls of the diaphysis.

Epiphysis

The wider region at each end of the bone, filled with spongy bone.

Metaphysis

The junction where the epiphysis meets the diaphysis, containing the growth plate and hyaline cartilage.

Epiphysed Plate

The growth plate located within the metaphysis.

Intramembranous ossification

The bone formation process occurring in skull, collar, and mandible bones involving mesenchymal cell grouping, osteoid secretion, trabecular matrix and periosteum formation, and compact bone development.

Endochondral ossification

The bone formation process occurring in all long bones of the body, where mesenchymal cells differentiate into chondrocytes to create a cartilage model that is subsequently penetrated by capillaries.

Reserve zone

The region of the epiphyseal plate closest to the epiphyseal end.

Proliferative zone

The layer of the epiphyseal plate toward the diaphysis containing stacks of larger chondrocytes.

Zone of maturation and hypertrophy

The epiphyseal plate region where older and larger chondrocytes are located.

Zone of calcified matrix

The zone of the epiphyseal plate that is located closest to the diaphysis.

Modeling

The process of erosion of old bone along the medullary cavity and deposition of new bone beneath the periosteum, increasing the diameter of both the diaphysis and the medullary cavity.

Remodeling

The process where the reabsorption of old or damaged bone takes place on the same surface where osteoblasts lay new bone.

Calcitriol

The active form of Vitamin D that stimulates the absorption of calcium.

Parathyroid hormone and calcitonin

Hormones that affect osteoclasts to regulate calcium levels.

Hypocalcemia

A condition characterized by abnormally low calcium levels.

Hypercalcemia

A condition characterized by abnormally high calcium levels.